1. Field of Invention
This invention relates to swim fins, a foot-mounted fin for use by body surfers and other swimmers and divers.
2. Description of Prior Art
Swim fins are designed to increase the swimmers mobility and speed in the water while at the same time reducing the amount of energy required to be expended.
Originally swim fins were designed to mimic the fins or flippers of aquatic animals. They were generally made of a solid piece of rubber or plastic that contained some means of attachment to the foot. While these designs did increase the power of the swimmer's thrusting motion, they did not maximize the hydrodynamic principals involved.
Later designs such as U.S. Pat. No. 3,649,979 to Mac Niel (1972), U.S. Pat. No. 3,913,158 to Vilarrubis (1970), U.S. Pat. No. 4,083,071 to Forjot (1978) and U.S. Pat. No. 4,627,820 to Penebre (1985) included different types of "scoop" portions to take in water, allowing it to pass through the fin and be released at the tip of the fin or close to it. Although this is an improvement, it still does not provide for efficient channeling of the water to the back side or bottom surface of the fin while at the same time releasing it at the tip. This flaw prevents the swimmer from fully utilizing the power potential of the water flow over the surface area of the fin.
U.S. Pat. No. 3,183,529 to Beuchat (1965), U.S. Pat. No. 3,055,025 to Ferraro (1962), U.S. Pat. No. 3,422,470 to Mares (1967), U.S. Pat. No. 3,922,741 to Semela (1974) and U.S. Pat. No. 4,775,343 to Lamont and Chapelas (1988) are designed to channel water to the back side or bottom of the fin. However, without a specialized portion of the fin to actively direct the water to the channels, these designs fail to deliver the maximum use of water power to the swimmer. Also, some of these types of fins are too big and bulky for effective use by swimmers and body surfers.
All of the swim fins previously known suffer from a number of disadvantages:
(a) Previous designs fail to channel the water effectively and therefore do not maximize the effect of the water flow over the entire available surface of the fin. PA1 (b) Many previous designs are too big and bulky, reducing the swimmer's mobility in the water and requiring unneeded expenditures of energy. PA1 (c) Some designs are too short, failing to provide maximum stroke efficiency in the water. PA1 (d) Some designs are too complex, resulting in a cumbersome device that defeats the basic purpose of the fin by decreasing mobility and agility in the water. PA1 (e) Some fins are designed to be used exclusively by divers while others can be used only by swimmers, necessitating buying different fins for each activity. PA1 (f) No previous designs provide any means for reducing the natural friction that occurs between the user's foot and the fin which can cause abrasions along the wearer's toes and foot. PA1 (a) The addition of a scoop or bridge portion across the top part of the fin forces the water through the main body of the fin and releases it at the tip of the blade portion and at the same time guides it to the eyelet channels to be released out the back side or bottom surface area of the swim fin. This design makes the optimum use of the flow of water by directing jet streams of water over all surfaces of the fin, giving the swimmer increased power with each kick stroke while at the same time reducing the amount of energy output required. PA1 (b) Having the water intake further down the face of the fin and farther away from the foot portion results in increasing the amount of water the fin is able to take in, and discharge at the tip of the fin blade. PA1 (c) Extending the scoop or bridge portion past the main body of the fin has the effect of combining the force of the jet stream of water from the eyelet channels with the jet stream of water from the bridge or scoop, thereby increasing the amount of energy released at the tip of the fin blade. PA1 (d) Eyelet channels formed into the main body of the fin just below the foot area and traveling towards the tip of the fin in a row on both sides of the center rib increase the efficiency of the fin by utilizing the flow of water or ocean current and directing it to the back surface area of the fin. PA1 (e) The seven embodiments of this fin can be designed in different lengths, enabling the swimmer or diver to choose which style would most improve his/her agility in the water. PA1 (f) The special lining of the foot chamber with a polyurethane product with a shore hardness of 5-20 acts as a chushion and reduces friction along the swimmer's foot thereby resulting in a more comfortable fit and eliminating abrasions caused by friction with the stiffer blade rubber. PA1 (g) This design offers all of the advantages of a complex system in a streamlined package.